A fundamental problem in video coding is prediction of high resolution images using available low resolution data. Least square (LS) filters are commonly used in these cases, and the LS filter coefficients are used to produce higher resolution images using available low resolution data, possibly from different times.
Zooming requires utilizing data possibly from different times and combining the available information to obtain a high resolution image for the current time. The training of the LS filters is possible by generating decimated images and finding the best set of LS filters to obtain back the original images minimizing the different between the original and predicted images.
A filter tap is a pattern overlaid on a region of pixels. The pixels overlapping the filter tap form the basis of filter coefficients associated with that pixel.